Hydraulic Conductivity and Pollutant Dispersion Coefficient Assessment During Leachate Flow in Unsaturated Clay

The use of TDR methods allows for the determination of the moisture profiles and the soil electrical conductivity profiles. Associated to the model of van Genuchten describing the water characteristic curve, the unsaturated hydraulic conductivity is computed. It is found that the leachate hydraulic conductivity is little greater than the water hydraulic conductivity. It is also found that the solute convection rate and the infiltration rate yield to the same value. A long time infiltration is necessary before the application of the Darcy law to determine the coefficient of permeability. The two models used to describe the hydraulic conductivity are in agreement. The influence of the leachate is not on these models. The dispersion coefficient becomes constant after 100 days of infiltration. The analytic solution of the convective-dispersive equation is a good approach of the solute concentration profile.